In metal framing systems for storefronts, curtainwalls, and windows, the framing members utilized in such construction are typically extruded aluminum profiles. Since such metal framing profiles form the facade of a building and are therefore directly exposed to the weather elements, the framing members are subject to thermal expansion and contraction. It is therefore conventional practice to provide a small expansion space between abutted framing members in long runs of lineal framing to accommodate such thermal expansion, particularly in the sill and header components of the framing system.
Such expansion joints must be sealed so that they are watertight and airtight to maintain the functional integrity of the framing. According to conventional practice, an expansion joint is covered by a thin metal plate that has one end bonded to one of the abutting framing members with a curing sealant. This other end is separated from the other framing member with a non-drying, non-curing mastic that serves as a sealant. Initially, this joint seal functions properly. However, under repeated thermal cycling and exposure to the elements over time, the seal tends to rupture, compromising the integrity of the joint.
Thus, there is a need to provide a seal for expansion joints in metal framing systems which will not rupture under repeated movement and exposure to the elements.